Miele Refrigerator F1 — Refrigerator Temp Sensor Short

What it means

Miele refrigerator F1 means the NTC temperature sensor in the refrigerator compartment has shorted (resistance has dropped to near zero).
The control board can't read the compartment temperature, so it falls back to a fail-safe duty cycle that may run too cold or too warm.
Food storage is unreliable until the sensor is replaced.
F1 is paired with F2 (open circuit on the same sensor) — both point at the refrigerator NTC, just different failure modes.

Affected Models

Miele K-series built-in refrigerators
Miele KFN combi fridge-freezers
Miele KS freestanding refrigerators
Miele MasterCool side-by-side units

Common Causes

NTC temperature sensor failed internally (most common)
Sensor wire harness pinched or shorted to chassis
Moisture in the sensor connector at the back of the unit
Control board input has failed (rare — usually points to the sensor first)

How to Fix It

Power-cycle the refrigerator.

Switch off at the wall socket or breaker.
Wait 5 minutes.
Switch back on.
If F1 clears and stays clear for several hours, it was a transient sensor glitch — keep an eye on it but you may not need a repair.
Check the sensor connector.

On freestanding models, pull the unit forward and access the connector strip on the back.
Built-in models require removing the air grille at the bottom front to reach the diagnostics port.
Inspect the NTC connector for moisture, corrosion, or a loose pin.
Reseating the connector clears a meaningful share of F1 cases.
Test the NTC sensor resistance.

A working Miele refrigerator NTC reads around 5 kΩ at 25°C (77°F).
Below 1 kΩ at room temperature is a short — replace the sensor.
Use a multimeter on the disconnected sensor; never measure with the unit powered.
Replace the sensor.

Order the correct NTC for your model — the part number is in the service documentation or on Miele's parts site.
Generic NTC thermistors with the same resistance curve work but Miele-branded parts are warranted.
Replacement involves disconnecting power, removing the old sensor from its clip, plugging the new one in, and securing the wire with the original clips.

When to Call a Professional

If you're not comfortable working behind the back panel of a built-in Miele, call a Miele-authorised technician.
The sensor itself is inexpensive but locating and replacing it cleanly on a built-in column unit involves pulling the cabinet — that's the part that takes skill.

Frequently Asked Questions

Will food spoil while F1 is showing?

It depends on what the fail-safe duty cycle does on your specific model.
Some Miele units run the compressor at a fixed default that keeps food reasonably cold (around 5°C) but with poor consistency.
Others stop cooling altogether when the sensor is unreadable.
Check actual compartment temperature with a separate thermometer if F1 has been showing more than a few hours.